This from the city on dealing with the emerald ash borer, which is, even at you read this, spreading through Kentucky:
The Lexington Tree Board has issued a citizen advisory that makes general recommendation about treating ash trees for the emerald ash borer. The insect has devastated ash tree populations in northern states and has been found in central Kentucky and Lexington. Many ash trees located on public and private property already have been found to be infested.
“There are more than one-half-million ash trees in Fayette County,” said Karen Angelucci, Tree Board Chair. “Every ash tree is at risk of being severely affected or killed by the insect unless they’re successfully treated.”
The tree board handout that provides information about treating ash trees is available through the city’s web site at:
The handout offers some simple instructions on determining if a homeowner can treat a tree themselves or should seek professional help from a certified arborist or tree specialist.
For trees that can be treated by a homeowner, mid-to-late Spring is the best time to treat ash trees with an insecticide available at most larger garden supply or nurseries. Larger trees that require professional insecticide injections should also be treated in the Spring.